STUDIES ON THE GROWTH, GAIN AND CARCASS V ALUE OF PRIMIPARA DURING SINGLETON AND TWIN PREGNANCIES .3. QUALITY OF CARCASSES AND LEAN MEAT OFPRIMIPARA

The animals used for the study represent a suckling cow management mod el, and a single calving of hybrid cows (Simmental or Charolais x-Frie sian Holstein, combined dairy and beef cattle), the slaughter of the c ow immediately after weaning and four feeding levels (EN) before calvi ng were foreseen. The nutritional level before calving had a positive effect on live weight, carcass yield, edible fat, intramuscular fat co ntent and tenderness, The higher nutritional level of the heifers preg nant with twins before calving was insufficient to achieve the same we ights at calvin as after singleton pregnancies. Carcass yield, interna l fat, intramuscular fat content and the fat content of the meat decre ased as the duration of lactation increased, and the meat became less tender. Not all of the cows met the criteria for brand-named meat prog rammes with respect to lean meat quality (muse. long, dorsi, frozen fo r 24 h). There were no significant differences between the heifers whe n they were inseminated and the young cows. The proportion of intramus cular fat in the cows was considerably higher than the required value of >2.5 %. The fondue loss criterion was also met, being less than the required 45.1 % in all cases. The shear value used as a measure of te nderness was in all cases higher than the expected value of <10.6 kp. Tenderness could possibly be improved by an appropriately high nutriti onal level before calving (1.3-1.4), possibly by reducing the lactatio n time to not more than eight weeks and reducing the slaughtering age to 24 months, but further studies are needed in this respect. An induc ed twin pregnancy would have to be dispensed with if the age of slaugh tering is reduced, say, by earlier conception. None of the animals ach ieved a sufficiently light colour of the meat, the values all being su bstantially below the optimal range of 15.1-22.5 Rem %. Lighter colour ed meat could be achieved by weaning the calves two days before-slaugh ter and using an easily digestible carbohydrate feed before slaughteri ng. After tenderness and the colour of the meat have been improved, it would be possible to produce high quality beef meeting the requiremen ts for brand-named meat programmes using young cows of the commercial hybrid Charolais or Simmental x Holstein Friesian.